*If you can't get English cucumber, try to find a Persian cucumber instead. A field cucumber can work in a pinch, but you will have to peel and seed it.
**If your like thick tzatziki, strain the yogurt first. All you need is a strainer, a bowl, and some cheesecloth. Fold the cheesecloth a few times so it forms several layers and lay it inside the strainer. Set the strainer over the bowl. Pour the yogurt into the lined strainer. Let this sit in your fridge for anywhere from a half an hour to overnight, depending on how thick you want the yogurt.